@article {338, title = {From State- to Delta-based Bidirectional Model Transformations: the Symmetric Case}, year = {2011}, month = {05/2011}, institution = {Generative Software Development Laboratory, University of Waterloo}, type = {Technical Report}, address = {Waterloo}, abstract = {Algebraic frameworks are important for building semantic foundations of bidirectional model transformations (BX). Symmetric BX are those for which neither model in a pair of synchronized models fully determines the other. We build two algebraic frameworks for symmetric BXs, with one correctly implementing the other, and both being delta-based generalizations of previous state-based frameworks. We also identify two new algebraic laws---weak undoability and weak invertibility, which are important for both state- and delta-based setting.}, issn = {GSDLAB-TR 2011-05-03}, attachments = {http://gsd.uwaterloo.ca/sites/default/files/zMODELS11 - TR.pdf}, author = {Diskin, Zinovy and Xiong, Yingfei and Krzysztof Czarnecki and Ehrig, Hartmut and Hermann, Frank and Orejas, Fernando} }